This invention relates to an air induction system that may accommodate a standard flexible panel filter with a rectangular pleat block in a non-rectangular housing for a motor vehicle such as an automobile that may employ a passive noise attenuation system.
Air induction systems are used to provide clean air to a vehicle""s engine. Such systems generally comprise a flow body, a filter housing and an air filter. Air is received into the flow body through an air intake and passes into the filter housing through a filter. The filter removes contaminants and particles that may otherwise interfere with the operation of the vehicle engine. Clean air then passes to the engine to combine with fuel in the combustion chamber.
Just as air flows into the engine, noise from the engine may propagate out of the air induction system and eventually find its way into the vehicle""s passenger cabin. Such noise is generally undesirable. Manufacturers have accordingly developed both passive and active noise attenuation systems to reduce or eliminate such engine noise. One such passive system involves using the filter housing as an expansion chamber to deaden sound. As known, a particular frequency of a frequency range may be selected for enhanced noise attenuation. By tuning the filter housing to this frequency, sound traveling through the filter housing may cancel itself through destructive interference and result in noise attenuation. That is, the filter housing is sometimes designed to attenuate a particular frequency range.
Due to limited space within a motor vehicle, an air induction system using its filter housing as part of a passive noise attenuation system may result in the design of an asymmetrically shaped filter housing. To accommodate this shaped housing, manufacturers have designed air filters in asymmetric shape to fit within these housings.
Panel air filters for motor vehicle applications typically consist of a filtration medium, a support structure, and a seal. The filtration media can be cellulose based, synthetic based, or a combination thereofto achieve the desired filtration performance with respect to contaminant removal efficiency, service life, and flow restriction. Typically, cellulose media is the most cost effective.
A well known panel air filter design and manufacture method is a rectangular filter consisting of a rectangular pleat block of cellulose media, a support structure of expanded metal, and a flexible urethane foam material which joins and seals the support and pleat block and also forms the seal for interaction with air cleaner housing. This filter manufacture method has relatively low tooling investment costs and fast production rates. Currently in order to have an asymmetric filter with a non rectangular pleat block, non standard media processing techniques must be used, (Ref. U.S. Pat. No. 5,622,583) thus increasing the investment for manufacturing.
Another well known panel air filter design and manufacture method consists of injection molding plastic around a synthetic media where the polymeric properties of the frame and media create bond in the injection process. Typically, a rubber gasket is then fitted to the plastic frame to crease the seal for interaction with air cleaner housing. This filter manufacture method has relatively high tooling investment costs and slower production rates.
The present invention comprises a flow body and filter housing. As known, air passes through an air intake to the filter housing through a flow body and to an engine of a motor vehicle, such as an automobile. The filter housing has an opening of a particular shape to permit the passage of air. Unlike existing filter housings for motor vehicles, the invention has a filter support that has an outer perimeter suited to the shape of the filter housing opening and an inner perimeter suited to mount a standard filter. In this way, a standard filter may be adapted for use with filter housings having non-standard openings.
Moreover, the filter may utilize a rectangular in shape pleat block and be composed of cellulose, thereby lowering manufacturing cost of the air induction system. In addition, seals may be employed between the support and filter media as well as the housing and support so as to ensure the flow of air through the filter.
Another feature of the invention comprises a flow body, a filter housing, and a uniquely designed filter support. The support allows for the use of a standard rectangular pleat block air filter and also has an outer perimeter with at least two flanges extending from the inner perimeter of the support that mounts the standard filter. The filter may be rectangular, composed of cellulose, and have pleats. Seals may also be employed.
The invention permits the use of a standard rectangular pleat block filter with a passive noise attenuation system. The filter housing may attenuate engine noise by having a particular dimension tuned to a range of frequencies as known. However, rather than use a specially designed filter to fit within the unique shape of the housing, the invention employs a standard filter with a support having an outer perimeter of the shape of the housing to fit the housing and an inner perimeter of the shape of the filter to fit the filter. The filter housing may have a predetermined dimension of a quarter or a half wavelength of a frequency selected from the range of frequencies. Such a design results in the destructive interference of sound within the housing, thereby attenuating engine noise, which may be in the range of 60 hertz to 600 hertz.
The invention thus permits the use of a standard filter with a non-standard shaped filter housing.